Depending on the state laws, sometimes they can. I'm from Massachusetts and if you let your auto insurance lapse and not pay the premium, you'll have to pay the old premium before anyone else can insure you and they still have the option to turn you down! Go figure! But that's the way it is here. This could be true in Nebraska also. And, if you have outstanding parking tickets, you cannot get a registration (since that info is sent to the Registry of Motor Vehicles in this state after a certain time and you haven't paid). Parking tickets here never go away, they're kept in a database at the Registry. Remember, I'm going by Massachusetts laws, but the laws in your state may be similar if not exact.
I can only suggest that your brother pay the old premium if he owes any, the parking tickets may have to be paid too, no matter how old they are and then try his best to find an agency or company that will insure him.
By the way, age makes no difference here - it's a matter of paying the premium for the insurance and any tickets or moving violations you get.